KR100653327B1 - Improved edgecomb resistance polyester - Google Patents

Abstract

   FIELD OF THE INVENTION The present invention relates to polyester fabrics used in airbags, and more particularly to edge combs, which are properties of fabrics that tear under conditions of seam stress or similar action, such as the expansion of inflatable restraints. It relates to a polyester fabric having an improved resistance to). The polyester fabrics of the present invention should also have an edge comb resistance greater than about 350 Newtons at room temperature (20 ° C.) and greater than 250 Newtons at 90 ° C. The polyester fabric of the present invention has an acrylic polymer or copolymer finish, or a mixture of acrylic and non acrylic polymers. This finish is about 1-4 weight% nominal solid additive.

  Airbags, Polyester, Coatings, Edge Comb Resistance, Polymer

Description

Polyester with improved edge comb resistance {IMPROVED EDGECOMB RESISTANCE POLYESTER}

FIELD OF THE INVENTION The present invention relates to polyester fabrics used in airbags, and more particularly to edge combs, which are properties of fabrics that are pulled under seam stress or similar forces, such as the expansion of inflatable restraints. It relates to a polyester fabric having an improved resistance to). The polyester fabrics of the present invention should also have an edge comb resistance greater than about 350 Newtons at room temperature (20 ° C.) and greater than 250 Newtons at 90 ° C. The polyester fabrics of the present invention have a polymer brand finish that is suitable for acrylic polymers, copolymers, or nominal solid additives of about 1 to 4% by weight.

Conventional airbags are coated or laminated with elastomeric resins, such as synthetic rubbers such as chloroprene, chlorosulfonated olefins or silicones to provide a base fabric with low air permeability to plain weave fabrics. It is manufactured by cutting and sewing into a bag with the base fabric. Elastomer resins are suitable for the surface of the base fabric in amounts of 90 to 120 g / m ² , and the airbags produced are very heavy, hard and apparently rough. In addition, the airbag is hard to fold when folded into a compact module. If the base fabric is coated with a silicone elastomer resin, the airbag has significantly more heat and cold resistance than would be the case with an airbag coated with chloroprene elastomer resin on the base fabric. And the amount of the coated resin is only about 40 to 60 g / m ² , thereby reducing the weight and improve the appearance and foldability.

    Parker's US Pat. Nos. 6,545,092, 6,348,543, and 6,468,929 disclose coatings that improve edge comb resistance. This coating is a crosslinked mixture of polyalkyl / polyphenoxy siloxane and a copolymer of ethylene and methacrylic acid.

   Conen's US Pat. No. 3,705,645 discloses an acrylic polymer coating as a film laminate inside an airbag.

   Gossack's U.S. Patent No. 5,800,883 discloses polyurethane resins coated on airbags.

   Many others have used silicone resin coatings that produce films on top of the fibers to produce air impermeable airbags. These airbags exhibited reduced seam combing. It is also known to use silicone / urethane or silicone / acrylic copolymer coatings to improve tear strength.

   Lee's US Pat. No. 6,169,043 discloses airbags coated with polyacrylic acid and polyurethane copolymer resins to reduce air permeability. However, no mention is made of seam or edge combing. This patent shows that polyacrylic acid alone is inferior to polyacrylic acid and polyurethane copolymer resins in terms of air permeability.

   Moriwaki et al. US Pat. No. 6,291,040 discloses nylon airbag fabrics thinly coated with thermoplastic synthetic resins, preferably polyurethane or polyester base resins, to prevent edge combing by filling the gaps of the fabric with resins. Is starting.

   However, such improvements have not yet been recognized as sufficient. This coating must withstand extreme conditions when folded. For example, the coating should not be cracked or sticky, and the airbag may be seam combing (when stressed due to expansion) Must be developed without relative tendencies).

   In addition, it is required that the fabric for the airbag be less expensive and more easily foldable to reduce the size of the module. So uncoated airbags are attracting attention. However, such airbags are broken during sewing and exhibit seam coaming.

   Uncoated nylon fabrics for air bags have better edge comb resistance than polyester fabrics used for the same purpose. In order to make polyester airbags that can compete with nylon airbags, it is desirable to increase the edge comb resistance of the polyester fabric used in the airbag. It is therefore necessary for uncoated polyester airbags to exhibit equal or better edge comb resistance at ambient and elevated temperatures.

   The present invention recognizes that polyester airbags have inferior edge coaming resistance compared to nylon airbags. Nylon airbag fabrics have an edge coaming resistance of at least 350N at room temperature and greater than 250N at 90 ° C. The present invention does not utilize film-forming webs on airbag fabrics in order to increase the edge coaming resistance of polyester airbags and not affect air permeability. In fact, the present invention utilizes a finish that coats the fibers of the fabric but does not form a film on the fabric itself. In this way the finish greatly improves the edge coaming resistance without affecting other fabric properties such as foldability.

    In the broadest sense, the present invention relates to knitted polyester fabrics having edge coaming resistance greater than 350N at room temperature and greater than 250N at 90 ° C.

    In the broadest sense the invention also relates to a polyester airbag having an edge coaming resistance greater than about 350 N at 20 ° C. and greater than about 250 N at 90 ° C. and having an acrylic ester polymer finish.

    In the broadest sense the invention also relates to a polyester airbag having an edge coaming resistance greater than about 350 N at 20 ° C. and greater than about 250 N at 90 ° C. and having a finish which does not form a film.

    In the broadest sense the invention also relates to an elastomeric coated knitted polyester fabric having an edge coaming resistance of greater than about 350N at room temperature and greater than about 250N at 90 ° C.

Preferred embodiments of the present invention are described in detail below.

In an extremely simplified form, the present invention relates to a polyester fabric having a finish of an acrylic ester polymer. Polyester fibers and fabrics for airbags are well known. Inviser Incorporated, former Cosa, sells an inconspicuous fiber named 650d T771.

Polyethylene terephthalate (PET) homopolymers are prepared by one of the following two processes. That is, 1) ester interchange process and 2) direct esterification process. In the ester interchange process, dimethyl terephthalate (DMT) is reacted with ethylene glycol (ester exchange), with bis (2-hydroxy ethyl) terephthalate (monomer), and methanol with a small amount of other reactants. Create Since the reaction is reversible, it is necessary to remove the methanol to completely convert the raw material into a monomer. It is known to use magnesium and / or cobalt and / or zinc in the transesterification reaction. At the end of the transesterification reaction, the catalytic activity disappears by introducing phosphorus in the form of polyphosphoric acid (PPA), for example. The monomer is then subjected to a condensation step (polycondensation) which is polymerized with PET. When monomers undergo polycondensation, the most frequently used catalyst is antimony. If the catalyst used in the transesterification reaction does not disappear with phosphorus, the resulting polymer is easily sensitized and has a very unacceptable yellow color.

The second method of preparing PET is to react terephthalic acid (TA) with ethylene glycol by direct esterification to produce bis (2 hydroxyethyl) terephthalate, oligomers, and water. This reaction is also reversible and can be completed by removing water during the reaction process. This direct esterification procedure does not require a catalyst and typically does not use a catalyst. As in the DMT process, monomers undergo polycondensation to form PET. Polycondensation reactions generally use antimony as a catalyst, but titanium in the form of titanium compounds is also a related general catalyst.

The polyester homopolymers of the present invention are then spun, drawn and relaxed and wound on bobbins described in Devebenditis et al. In US Pat. No. 6,471,906. This patent is hereby incorporated by reference and describes a suitable process for making the fibers of the present invention. Other known processes for relaxing the fibers can also be used in the present invention if such processes achieve at least 8% relaxation. Weaving the fibers into flat 1 × 1 fabrics can be done using conventional equipment known to traders. Typical fabrics are 42 x 42 spins per inch (16.5 x 16.5 spins per cm).

The term " acrylic acid ester polymer " means a polymer comprising at least partially structural units derived from acrylic acid esters. Typical monomers include methyl, ethyl, n-butyl, iso-butyl, 2-ethylhexyl, and octyl acrylic acid and mixtures thereof. This not only means acrylic ester homopolymers. Also included are copolymers of acrylic acid esters such as methacrylate, styrene, vinyl acetate, polyester, acrylonitrile and other polymerizable monomers. Mixtures of acrylic esters with other polymers are also included.

Acrylic ester polymers include Rohm & Haas (Rhoplex®), Eastman Chemical (copolymers of Rheoprint®-acrylic acid esters and polyesters, copolymers of Qualbond®-polystyrene and acrylics), National National Starch (Nacylic®), and B.F. It is commercially available as a fabric binder from Hycar®.

The acrylic ester polymer is diluted in a water solution and applied to plain weave fabrics with about 1-4% by weight nominal solid addition. More preferably the finish is applied to the fabric at about 1 to 2% by weight solid addition. The finish may be applied by spraying, dipping, brushing, meniscus rollers, or other known suitable process. Preferably applied by immersion.

The finish is applied onto the fabric and dried (using an oven or using a Rom temperature drying method) and then tested for edge coaming resistance. Uncoated nylon fabrics are known to have an edge comb resistance of at least 350 N at room temperature. Therefore this is the minimum resistance suitable for the present invention.

Test procedure

Edge comb resistance of the woven fabric was measured according to ASTM (American Society for Testing Materials) D6479-02, using a 50 mm wide fabric strip. The measurement was performed at 20 degreeC and 90 degreeC. One end of the specimen is clamped in a jaw of the CRE tensile tester, and a special fastener penetrates the opposite end of the specimen and is embedded in equally spaced needle holes. In accordance with Test Method D 5035, a tensile force is applied until the specimen ruptures. The measurement of the force required to cause the rupture is the measurement of the edge comb resistance. The finish glass transition temperature (Tg) is measured by DSC at 10 ° C./min from 10 ° C. to + 50 ° C. using a 10 mg sample. The sample is dried in a desiccator for 12 hours before measurement.

Example

Unless otherwise noted, the yarn is woven into plain weave with a nominal 42 × 42 tip per inch (16.5 × 16.5 tip per cm). Woven fabrics are each scoured at 60 ° C. and dried at 177 ° C. in the conventional manner. The woven fabric is immersed in the diluted resin solution of the acrylic fabric finish. The fabric is gently pressed at ³ Kg / cm ² by mangles. The woven fabric is thermally fixed at 160 ° C. for 45 seconds to obtain a base fabric for the air bag. The nominal solid addition of the acrylic finish was 1.5% by weight.

Example 1 (control)

Base polyester and nylon fabrics were prepared following the usual procedure without immersion in the binder finish. Yarns were obtained from the Invista Company of America. The edge comb resistance of these fabrics is shown in Table 1. In addition, the base fabric was sewn and deployed with a passenger side airbag module. After 4 hours of heating at 90 ° C., it was shown whether there was coaming in the seam when the module was deployed.

Table 1

 Yarn  Denier Edge comb resistance, N  Incoming Coming  20 ℃  90 ℃ T769 nylon 630 370 330 none T771 polyester 650 300 250 has exist

These results show the superiority of uncoated nylon relative to uncoated polyester for seam coaming.

Example  2

The 650 denier T 771 woven fabric described in Example 1 was immersed in another container of acrylic base binder purchased from Eastman Chemical Company of America. The finish levels and edge comb resistances are shown in Table 2. This explains the fact that various acrylic base finishes significantly increased the edge comb resistance of polyester fabrics. Visual inspection of the fabric shows that the finish is coating individual spinning filaments and there is no film formation on the fabric.

TABLE 2

Binder Finish Finish Tg, ℃ Finish, Weight% Edge comb resistance at 20 ° C, N none - - 300 Rheoprint 2000 -16 2 945 VC-1 -12 2 790 Builder 545 -18 3 835

Example 3

Base polyester and nylon fabrics were prepared following the general procedure. Nylon fabric is a plain weave fabric with 41 × 41 ends (16.1 × 16.1 ends per cm). Rheoprint 2000 (polyester-acrylic finish with Tg of -16 ° C) and Qualbond (polyethylene-acrylic finish with Tg of + 13 ° C) finishes were applied to the polyester base fabric. Edge comb resistance was measured at 20 ° C. and 90 ° C. and the results are shown in Table 3.

TABLE 3

Weaving finish Edge comb resistance, N 20 ℃ 90 ℃ 630d nylon T728 none 370 330 650d polyester T771 2 weight% Rheoprint 830 280 650d polyester T771 1 wt% Qualbond 585 435

This example shows that the addition of low levels of acrylic fabric finish significantly increases the edge comb resistance of the polyester fabric at 90 ° C. Moreover, finishes with higher Tg maintain higher edge comb resistance at 90 ° C. Visual inspection of the fabric with the binder finish shows that it is coated on the individual spinning filaments and there is no coating on the fabric. This was confirmed by measuring unchanged air permeability from the uncoated base fabric.

Example 4

Fabrics containing 440 denier T791 polyester filament yarns were woven, washed and treated with 1 wt% and 2 wt% Rheoprint 2000 fabric finishes. These treated fabrics were coated with a two part liquid silicone rubber (30 g / m ² ). Edge comb resistance of uncoated and coated fabrics was measured at room temperature (20 ° C.) and the results are shown in Table 4.

Table 4

Rheoprint, weight percent Edge comb resistance, N Uncoated coating 0 410 500 One 620 550 2 690 690

This example shows that acrylic finish is a major contributing factor to the improvement of edge comb resistance in airbag fabrics coated.

As mentioned above, according to the present invention, there is provided a polyester fabric having an acrylic base finish that fully satisfies the above-mentioned objects, objectives and advantages.

      The foregoing description and examples merely illustrate preferred examples of the invention and its principles, and various modifications may be made by those skilled in the art without departing from the spirit or scope of the invention. And they may be included in the scope of the appended claims.

Claims (15)

Woven polyester fabric characterized by having an edge comb resistance of greater than 350 newtons at room temperature and greater than 250 newtons at 90 ° C. The woven polyester fabric of claim 1, wherein the fabric has a finish that does not form a film thereon. 3. The woven polyester fabric of claim 2, wherein the finish is an acrylic base. 4. The woven polyester fabric of claim 3, wherein the finish is about 1 to about 4 weight percent nominal solid additive. 4. The woven polyester fabric of claim 3, wherein said acrylic base finish is an acrylic ester polymer. 6. The woven polyester fabric of claim 5, wherein said acrylic ester polymer is prepared from monomers comprising methyl, ethyl, n-butyl, iso-butyl, 2-ethylhexyl, and octyl acrylic acid and mixtures thereof. 6. The woven polyester fabric of claim 5, wherein said polymer is a copolymer of acrylic esters and other polymerizable monomers. 8. The woven polyester fabric of claim 7, wherein said polymerizable monomer is selected from methacrylate, styrene, vinyl acetate, acrylonitrile. The woven polyester fabric of claim 1, wherein the fabric is a plain weave fabric of about 42 × 42 yarns per inch (about 16.5 × 16.5 yarns per cm). The woven polyester fabric of claim 1, wherein the fabric is coated with an elastomer. A polyester airbag having an edge comb resistance of greater than 350 newtons at 20 ° C. and greater than 250 newtons at 90 ° C. and having an acrylic ester polymer finish. 12. The polyester airbag of claim 11 wherein the acrylic ester polymer is prepared from monomers comprising methyl, ethyl, n-butyl, iso-butyl, 2-ethylhexyl, and octyl acrylic acid and mixtures thereof.       12. The polyester airbag of claim 11, wherein the polymer is a copolymer of acrylic esters and other polymerizable monomers. The polyester airbag of claim 13 wherein the polymerizable monomer is selected from methacrylate, styrene, vinyl acetate, acrylonitrile. 12. The polyester airbag of claim 11, wherein the finish is about 1 to about 4 weight percent nominal solid additive.